I can be in the UK for up to 6 months without a visa with my US passport, and I'm at a stage in my life where living in London and traveling the rest of Europe from there would be a lot of fun and I have the ability to do so. I realize I can do this from other places, but have a number of reasons for choosing London so I'd like to keep suggestions away from "why not city X instead" please :) Also, I have the money to be able to do this, within reason. I definitely don't want to live in a tiny box, but I'd rather not spend 3000 GBP/month either if I can avoid it.

What do I need to know in terms of looking for a place? Obviously it's going to be expensive, and I'll need something furnished and with utilities since I won't be there longer than 6 months. I've been looking at RightMove for furnished short lets and also GumTree, is there anything else?

I'm hoping to be in zone 1 or zone 2, are there areas that have more crime or are a bit shady that I should avoid? I've also seen on RightMove that some areas seem to have much slower internet than others...I'd like to be able to have good enough internet that I could video chat with friends back home without having to go to a coffee shop or something.

Without having a credit rating or anything in the UK, will I be restricted in terms of where I can rent from?

I definitely don't want to live in a tiny box, but I'd rather not spend 3000 GBP/month either if I can avoid it.

In London with all inclusive furnishings and utilities including internet? You're probably looking at either one or the other.

You may be better looking at renting a room in a shared house or something, a lot of people do that. Landlords generally want some sort of rent and work history, references etc for renting out full properties, even short term. And if you're using it as a base for exploring the UK and going on day/week trips to Europe etc, do you really need much more than somewhere to fix some food, report back to colonial HQ and get your head down?

Make sure you do your homework on the smallprint of that non-visa thing, by the way. I'm not 100% sure how it would be affected if you're regularly leaving the country on trips to mainland Europe and it'd definitely suck if you got turned away at customs on your way back in because of a technicality in the visa waiver programme.

You should be able to find a houseshare / room for rent fairly easily, much easier than finding a short term let for your purposes and circumstances I'd imagine.

As for specific places to look, not living in London myself I'm unfamiliar with the best agencies and so on to look for, perhaps someone more local could chip in with specific recommendations as to who's reputable and willing to cater to your circumstances.

For entry into the UK, you need to have sufficient ties to the US that will convince the immigration officer you will return.

What level of proof is typically required here? Would an address and job in the US be sufficient? Receipts for season tickets for a sport in the US that's in the fall?

For renting a house, no proper landlords will rent to you unless you pay the full 6 months upfront; some may be prepared to do so informally with cash payment and no tenancy agreement

Sounds reasonable, especially since I won't be able to prove credit worthiness other than with financial statements / pay stubs. What would the lack of a tenancy agreement mean? Wouldn't that put me more at risk and make it more difficult to show I have a place to stay when going through immigration?

A lack of a tenancy agreement is a big nono; never go into an accommodation without a tenancy agreement: its basically a contract. Without one, the landlord can kick you out with no notice, demand extra money... all sorts of nasty things.

Probably not. You need to prove you have enough cash in your bank account that you don't need to work for 6 months, plus having a tenancy would probably raise a flag, it's better to "stay with family". If you're traveling solo you need to prove an exit strategy. If you're planning on traveling throughout Europe you're better off asking for the length of your first stay and going through the process every time, rather than declare the time London will be your base.

I'll be able to prove I have the cash in my accounts, but I don't really know how I'm supposed to prove travel plans and a place to stay to immigration but that tenancy would raise red flags...wouldn't showing tenancy that's for 6 months or less demonstrate that I don't plan on staying longer?

Makes sense. My plans are to live in London, explore the city and rest of the country with friends (I know a decent number of people in London and a few other cities farther north), and take trips to the rest of Europe. Then after 3-6 months, return to the States.

i'd get that all written out and booked/planned in detail for the entirety of your stay (especially your return/exit flights, no return flight or exit flight is nearly automatic detention). unfortunately, it really depends on the border guard, but its better to be safe than detained or sent back.

It's because you had the audacity to mention London, let a lone a preference for it over the rest of the UK, which is a faux pas out side of the south east.

As for your question, it really does depend on your budget. Places near Finsbury Park are quite cheap, some areas are a little rough but absolutely nothing like the rough areas of large US cities. Also if you can bear being a little further out then Walthamstow is quite cheap as well. Both Finsbury Park and Walthamstow are within easy reach of central London.

you have enough money to support and accommodate yourself without working or help from public funds, or you and any dependants will be supported and accommodated by relatives or friends;

For this you need to show that you have enough money plus a reserve to stay for your desired trip, if you are intending to live in London then be aware the baseline would be pretty high to live here for 6 months. Don't even mention anything remotely construed as work or you'll be on the first flight back to America

you do not intend to live in the UK for extended periods through frequent or successive visits

I'm pretty sure using the flat as a base may flag up a few red flags if you keep appearing at the border every few weeks, all it would take is one arsehole working and you'd loose access to the flat. protip though, border staff seem to be a lot nicer outside the huge airports (heathrow, manchester)

Overall British City internet is above and beyond America's speeds and you'd never find a problem using stuff like Skype, fibre (100mbps, heavily debated in /r/uk) is in nearly every city, you could even pick up a SIM with unlimited internet for cheap. www.police.uk is a map showing crime in the UK but by and large you won't really experience much in Zone 1/2 aside from a drunk or two

If you want a base to travel Europe you could easily live in Birmingham or Manchester as they both have big airports with a lot of routes as well as being great cities to live in. And then move to London for a couple of months when you actually want to stay there. There's no point paying through the nose for London rents if you aren't even going to be there.

Don't forget to apply for a multiple entry Schengen visa if you are going back and forth between the UK and Europe